Bi-polar transistor devices are known and commonly comprised of selectively impurity doped semiconductor regions within a semiconductor material substrate each of which regions are in communication with other of the transistor regions. As is also known, transistor operation is at least partially dependent on application of externally provided electric fields to portions of the regions which form semiconductor junctions within the transistor.
Known means for providing the electric fields include operably coupling appropriate voltage sources to conductive ohmic contacts disposed on selected regions such as, for some examples, an ohmic contact to the base region, an ohmic contact to the emitter region, and an ohmic contact to the collector region.
Some applications of transistors include signal amplifiers such as radio frequency (RF) and microwave frequency amplifiers. Transistors employed for such applications are susceptible to failure induced by high voltage reflected waves which may appear at the transistor terminals. As such it is frequently necessary to provide protection circuitry to reduce the possibility of damage to the transistor(s).
Further, known bipolar transistors have associated therewith a leakage current that is present in those instances when the transistor is operated in an OFF mode during which time no current is desired.
Accordingly, there exists a need for an improved transistor device which overcomes at least some of these shortcomings of the prior art.